US2315062A - Method and means for controlling honing operation by expansion - Google Patents

Description

March J. E. KLINE j 2,315,062

METHOD AND MEANS FOR CONTROLLING HONING OPERATION BY EXPANSION Filed Feb. 18, 1939 s Sheets-Sheet 1 v i INVENTOR 0%)? Z: 26-

TORNEYS.

March 30, 1943. J. E. KLINE METHOD AND MEANS FOR CONTROLLING HONING OPERATION BY EXPANSION Filed Feb. 18, 1959 a Shets-Shet 2 11y VENTOR J. E. KLINE March 30, 1943.

METHOD AND MEANS FOR CONTROLLING HONING OPERATION BY EXPANSION Filed Feb. 18, 1959 3 Sheets-Sheet 3 llv VENTOR E //ZZ/Z6. BY M544 2 S A TTORNE V51 Patented Mar. 30, 1943 METHOD AND MEANS FOR CONTROLLING HONIN G OPERATION BY EXPANSION John E. Kline, Grosse Pointe Farms, Mich asslgnor to Micromatio Hone Corporation, Detroit, Mich, a corporation of Michigan Application February 18, 1939, Serial No. 257,088

Claims.

This invention relates to grinding machines and especially to mechanism for individually and collectively controlling the abrading tools of a multiple spindl machine.

The principal object of the invention i to 1m prove the art of grinding machines.

It is also an object of the invention to provide control means for each abrading tool of a multiple spindle machine for causing such tool to effeet the operation for which it is set and then contracting the abradlng heads of each tool upon completion oi such operation.

A further object is to provide individual control means for each abrading tool of a multiple spindle machine which renders each tool effective until the predetermined operation for that tool has been completed, then retracts all of the abrading tools when the desired operations have been efiected.

Another object is to provide each abrading tool of a multiple spindle machine with a working expansion limiting means for maintaining each tool efiective'until full limit expansion operation for which it has been set is completed in con- Junction with control means for retracting all tools when all operations for which the tools were preset has been eiiected, and further to provide each tool with manually adjustable positive stop expansion limiting means efiectlve as a safety stop for limiting expansion of the tool to a slightly greater amount in the event that the working expansion limiting means fails to operate.

Other objectsfeatures and advantages will become apparent from the following description and appended claims.

For the purpose of illustrating the genus of the invention, a concrete embodiment is illustrated in the accompanying drawings, in which:

Figure 1 is a perspective view of a multiple spindle grinding machine constructed in accordance with the principles of this invention;

Fig. 2 is a side elevation with parts broken away and shown in section of one of the tool spindles depicted in Fig. 1;

Fig. 3 is a central vertical section taken centrally through drive and control means of one of the spindles depicted in Fig. 1, the associated parts being shown in elevation or in partial section;

Fig. 4 is a diagrammatic view-illustrating the control system for the multiple spindle grinding machine depicted in Fig. 1, and I Fig. 5 is an enlarged diagrammatic illustration of switch mechanism shown in Fig. 4.

Referring to the drawings, and more especially to Fig. 1, the numeral I 0 represents the work piece in the form of a cylinder block I0, having a plurality of cylinder bores l I which are to be ground, honed, or polished. such work piece being indicative of any multiple cylinder block of a gas engine, steam engine, or compressor, or similar apparatus and adapted to be held stationary on an appropriate support of the machine illustrated by any suitable fastening means, not shown. The abrading'machine comprises an upright column 12 terminating at its upper end in a main housing- 13, having an auxiliary housing Hi and I5 extendingforwardly from the upper end of the column for housing spindle drive mechanism Journaled in a reciprocating carriage or head I5 for a plurality of spindles I'l each comprising a driving portion 28, manually adjustable expansion stop means 2! and an abrading head 22. A guiding bracket at 23, preferably integrally built into the work holding fixture of the work piece Ill,

' is provided for centering and guiding the abrading tools into the bores ii of workpiece ID. A hydraulic cylinder 24 is disposed between the auxiliary housings it and It for moving the reciprocating carriage or head It toward and away from the workpiece for .the purpose of moving the abrading tools into and out of the bores l l of such workpiece it.

Reference may now be had to Fig. 2 in which the numeral 25 represents the body of the head portion 22 of the abrading tool and such body is provided with an axial bore 2%, a plurality of radial longitudinal driving grooves 2'1 extending through the body 25. A double cone 28 is axially movable within the bore 26 and makes a double contact at points 30 with stoneholder 3!, each of the latter carrying a stone 32 provided with end clips and maintained in assembled relation with respect to the stone holders by means of band or garter springs 33. The pitch of the double cone 38 is beyond the angle of reversibility, allowing the expansion mechanism to advance the cone, but preventing any amount of external pressure on the stones from reversing the action. This, in conjunction with the two point contact with the stone holders, assures straight cylinders and prevents the stones from following tapered or irregular bores. The upper end of the body 25 is externally threaded and secured by means of a rocker connection to the shank 3d. The rocker connection comprises a threaded sleeve 85, lock nut 36, packing 31, and anti-friction members 38. The upper end of the double cone 28 is connected by means of a universal joint 40 to a spindle ti. The rocker connection between the shank 34 and body 25, in conjunction with the universal joint 40, permits uniform transfer oi expansion pressure to the abrading tool and compensates for slight misalignment of the work with relation to the axis of the machine spindle. The upper end of the spindle4l i threadedly connected to a pin holder 42 for a pin 43 which projects through a slot 44 in the shank 34 and into an adjusting sleeve 45. The adjusting sleeve 45 is externally threaded and threadedly engages a knurled adjusting nut 46. The adjusting nut 46 is connected in a rotatable but not axially movable manner relative to a sleeve 41 by anti-friction members 48 and '58, the anti-friction balls 58 being biased upwardly into contact with the lower end of the sleeve 41 by means of springs and adjusting studs 52, and the anti-friction members 48 being maintained in position by means of a sleeve 53 pinned to the sleeve 41 by means of pins 54. A pin 55 fixed to the sleeve 41 extends through a slot 58 provided in the shank 34, the gap" between the pin 55 and the base portion of the slot 56 constituting the safety positive stop limiting means for regulating the expansion of the abrading tool in the event of failure of working expansion limiting means, later described, to function. The stop gap may be adjusted by retating the knurled adjusting nut 48 which, due to its threaded engagement with th adjustment sleeve 45, opens or closes the gap between the lower surface of the pin 55 and the bottom of the slot 56. Such positive stop expansion limiting means of the abrading tool is intended to be set slightly beyond the working stop limiting means, to be explained later, and to be employed only as a safety means to prevent grinding or honing a cylindrical opening materially oversize. The upper bore of the shank 34 is enlarged slightly to provide a shoulder 51 adapted to support a washer 58 and the lower end of a recoil spring 68,-the upper end of which abuts a pin 55 to effect contraction of the abrading tool head when compression on the expanding means, later described, is relaxed. The driver 28 of the abrading tool includes'a universal joint Bi and is connected to the upper end of the shank 34 by means of a pin 62 adapted to be maintained in assembled relation with respect to thedr'iver and shank 34 by means of a sleeve 63 and the latter is adapted to'be locked in position by means of a spring pressed detent 64. As previously indicated, the head assembly 22 contains all the expansion, actuating, and adjusting units, and the expansion of the abrading stones 32 is effected by hydraulic pressure on the push rod 65 by fluid pressure mechanism in the reciprocating carriage or head [8, depicted in Figur 1. This actuating pressure, carried through the center of the driver 28, automatically actuates the drive shaft push rod 88 and advances the double cone expander 28 through the adjustment mechanism included in the adjusting unit indicated generally at 2|. A slot 61 is cut through the drive shaft push rod 68 to permit axial movement of the latter without interference with the pin 62. I

Reference may now be had to Fig. 3 which indicates the fluid pressure responsive mechanism for effecting expansion of the abrading tool, control means for such fluid pressure responsive mechanism and rotating drive mechanism for the tool spindle. Each abrading tool isrotatably driven by means of a gear 18, keyed, as indicated at 1| in Fig. 3, to a. drive sleeve 12 journaled by means of-thrust bearings 14 to the reare driven by gearing 13, indicated diagrammatically in Figure4, and such gearing is driven from spindle drive mechanism housed within the auxiliary housings I4 and I5 of the abrading machine illustrated in Figure l. The gear sleeve 12 is threaded at its lower end and clamped to the driver 28 by means of the clamping sleeve 15 threadably engaging the lower end of vgear sleeve 12. Cylinder bores 16 are provided in the upper portion of the reciprocating carriage or head 16 in axial alignment with the axes of each of the tool spindles. A piston 11 is disposed in each of the cylinders 16 and is provided with a downwardly and axially extending stem 18 adapted to transmit pressure from the fluid compression chamber 88, which lies between the piston 11 and the closed or blind end of the cylinder 16, to the upper end of the push rod 65 for the purpose of expanding the abrading tool 22. Each piston stem 18 is provided with an enlarged portion 8! projecting through a stufilng box 82 which seals and closes the lower end of its cylinder 16. This arrangement also provides a fluid pressure expansion chamber 83 between the ciprocating carriage or head It. The gears 18 stufling box 82 and the lower end of the piston 11 so that vwhen fluid pressure within the latter chamber exceeds that in the fluid pressure chamber 88 the piston 11 will be elevated and allow the recoil spring 88 to collapse the abrading head 22. A solenoid operated valve, indicated generally at 84 in Figure 3, controls the admission of fluid pressure to the compression chambers 88 and 83 disposed at opposite ends of each piston 11. Each valve 84 comprises a cylindrical casing 85 provided with a central bore 86 which in turn is provided with five substantially equally spaced annular grooves 81. The return passage 88 connects the extreme right and left hand annular grooves 81 with each other but communicates with none of the other annular grooves 81. A 'return conduit 90 leads from the fluid return passage 88 to the source of pressure fluid as indicated in Figure 4. A plunger 9|, provided with a pair of spaced piston portions 92, is disposed in the bore 85 with the pistons 82 so spaced that when the plunger 91 is moved to the extreme right or left hand position within the bore 86, one piston will shut off communication between the adjacent outside annular grooves 81 at one end of the bore 88 while the adjacent outside annular grooves 81 at the other end of the bore 86 will be in communication with each other and the centrally arranged annular groove 81 will be in communication with the next adjacent annular groove on the other side. As illustrated in Fig. 3, the plunger 91 is moved to its extreme left hand position with the left hand piston 92 closing communication between the adjacent grooves at'the left hand end of the bore 86 and with the next to left hand groove 81 in communication with the central groove 81 while the right hand piston 82 closes the central groove 81 with respect to the next right hand groove 81 and the latter groove is in communication with the extreme right hand groove 81. A conduit 93 communicates with the next to the left hand annular groove 81 and with the fluid pressure chamber 88, while a conduit 84 communicates with the next to right hand annular groove 81 and the fluid pressure chamber 83. The pressure supply conduit 95 communicates between a pressure fluid and the central annular groove 81. Thus, with the plunger 9| in the position indicated, pressure fluid will flow from the conduit 95 through the central annular groove 81 to the next left hand annular groove 81, and through the conduit 83 to the fluid pressure chamber 88 and force the piston 11 downwardly to expand the abrading tool. At his time, the left hand piston 82 cuts oil co munication between the left hand groove 81 and the next to the left hand groove 81 so that there will be flow between the pressure supply and the return line and the right hand piston cuts oil communication between central annular groove 81 and the next right hand annular groove. The latter annular groove,

however, is in open communication with the righthand annular groove 81 and the return passage 88 so that pressure chamber 88 will be in communication through the conduit 84 and return passage 84 with the return line 88. Movement of the plunger 8| to the extreme right hand position will place compression chamber 88 in communication with the pressure supply counter 85 and the pressure chamber 88 in communication with the return line 88. This will elevate the piston 11 andallow the recoil spring 88 indicated in Fig. 2 to cause contraction oi the head of the abrading tool.

Solenoids 88 and 81 are provided at the right and left hand ends respectively of valve 84, as indicated in Figs. 3 and 4, and in the indicated position solenoid 81 is in energized condition while solenoid 88 is deenergized and pressure supply conduit 85 is in communication with pressure chamber 88 to eilect expansion the abrading tool.

The working expansion limiting means for the abrading tool is actuated by downward movement oi the piston 11 and to this end the lower end of piston 11 is beveled or tapered. as indicated at 88 in Figs. 3 and 4. A plunger I88 biased by means oi a spring I8I toward the bevel 88 of piston 11 is arranged in a suitable bore provided inthe reciprocating carriage or head I8'and is provided with a stem IMP-etc which is threaded an adjusting stud I88 adapted to be secured in adjusted position by means or a lock nut I84. The stud I83 is adapted to be adjusted and locked in the desired adjusted position to regulate the overall length oi the plunger I88 so that the letter, at the proper time, operates the micro switch I85 when'the piston 11 has descended the proper amount to efiect the desired expansion of the abrading tool.

Reference may now be had to Figs. 4 and 5 which depict the control system of a reciprocating carriage I8 and the six abrading tool spindles carried thereby. As indicated in Fig. 4, a micro switch I85 is provided for each of the tool spindles and each micro switch I85 controls the operation of a piston 11 through a solenoid operated valve 84, but one piston and solenoid operated valve being illustrated. Fig. 5 illustrates diagrammatically the two left hand micro switches I85 and the extreme right hand micro switch I85, shown in Fig. 4. Each oi.- the switches I85 include a pair oi! stationary contacts I88 and I81 mounted on a base plate I88 and adapted to be contacted by a terminal contact II8 carried by a snap spring conductor III which normally maintains the contact II8 in engagement with the stationary contact I88. The snap spring conductors I I I'are all connected to a power line I I2 leading to a suitable source of electrical energy, not shown. Another power line I I3 leads to one terminal of each of the solenoids 88 and 81 of each solenoid operated valve 84. The stationary contacts I88 are connected by conductors II4 to the remaining terminals oi the solenoids 81 while the stationary contacts I81 are connected by means of conductor H5 to the remaining terminals of solenoids 88. A third stationary contact I I8 is mounted on each switchboard I88 of the micro switches I and is adapted to be engaged by a contact I I1 carried by the snap spring conductor I II when'the terminal contact II8 engages the stationary contact I81. The snap spring conductors I I I are longitudinally forced to bowed condition between pivots II8 to engage contacts I I8 and I88 or to engage contacts II8 with contacts I81 and contacts II1 with contacts II6. It is noted that the contacts II1 are insulated by means of insulation I I8 from the snap spring conductors III. The contact II1 of the extreme left hand micro switch I85 is connected by means of a conductor I28 to a solenoid I2I, the remaining terminal of the solenoid I2I being connected by means of a conductor I22 to power line H3. The stationary contacts II8, except for that of the right hand switch, are each connected to the contacts II1 of the next microswitch to the right as viewed in Fig. 4. The contact II8 of the extreme right hand micro switch I85, as viewed in Fig. 4, is connected by means of a conductor I28 with the power line II2. Each micro switch I85 is provided with a switch actuating plunger I24 provided with an insulated tip I25 and these plungers are adapted to be actuated through the plungers I88, by pistons 11 to snap the spring conductors I I I to the left, as viewed in Fig. 4, in order to break contact between the terminal contacts II8 and stationary contacts I88 and cause the terminal contacts I I8 to engage the stationary contacts I81 and also to cause the contacts II1 to engage the stationary contacts II8. The solenoid I2I is adapted to operate a valve I28 controlling admission of fluid under pressure to either end of the cylinder 24 for lowering or elevating the reciprocating carriage or head I8. It is noted that the solenoid I2I is energized when all of the pistons 11 have been lowered to completely expand the abrading tools to the desired working limit to which the adjustment plungers I88 have been'set and all of the micro-switches I85 operated tosnap the spring conductors I I I to the left hand position, as viewed in Fig. 4. This closes the circuit from the power line II2 through the snap spring conductors III, contacts II1 and II8, conductor I28, the solenoid coil and conductor I22 completing the circuit to the other power line I I8. This causes the solenoid I2I to be energized and operate the valve I28 so that hydraulic cylinder 24 will elevate the reciprocating carriage or head I6 and remove the abrading tools from the work piece and guiding bracket 28. The valve I28 may be operated In the opposite direction by spring, gravity, or other desired means to cause the hydraulic cylinder 24 to lower the reciprocating head I6.

The pump I38 is interposed in the pressure conduit 88 between a fluid tank HI and the solenoid operated valve 84. The return conduit 88 leads back to the fluid tank I3I. The pressure conduit I82 may lead from the pressure conduit 85 between the pump I88 and the solenoid operated valve 84 to the control valve I28 or hydraulic cylinder 24. A return line I33 leads from the fluid pressure line I32 back to the tank I3I and a pressure regulator I84 may be interposed in this return line for regulating the pressure of the fluid supply tov thecontrol valve I28. A pressure regulator I35 may also be interposed in the pressure conduit 85 between the pump I 38 and the solenoid operated valves 84, the return conduit I88 leading from the pressure regulator I36 to the return conduit 88. A motor I81 or other suitable driving means is provided for operating the pump I30.

'Duringoperation of the abrading machine, the tool spindles II are rotated through gearing I4 and the spindle drive mechanism contained within the housings I4 and I5. Fluid under pressure supplied from the tank I3I by means of pump I30 backs through the control valve I26, solenoid I2I being deenergized at this time, to lower the spindle head I6 and lower the tool spindle II through the guiding bracket23 and into the bores II of work piece I0. Fluid under pressure is also supplied from the pump I30 through the pressure conduit 95 to the solenoid operated valves 84 and conduits 93 to the pressure chambers 80 for each of the two expanding pistons 11 in order to effect expansion of theabrading tool heads 22. At this time,,all of the micro switches I05 are in the positions indicated in Fig. 4 with the solenoids QI energized and the solenoid operated valves in the position indicated in Fig. 3. The solenoids 01 are energized by the electrical circuits including the power line II2, snap spring conductor I I I, terminal contacts IIO, stationary contacts I06, and conductors II 4, the solenoid coils completing the circuit through the solenoids 91 to the power line II3. Fluid pressure within the pressure chambers 80, forces pistons "II downwardly until each abrading tool head 22 has been expanded to the working limit for which the adjustable plunger I has been set,

so that when each plunger IT has been lowered sufliciently to snap its micro switch I to the left hand position indicated in dotted line in the left hand switch I05 of Fig. 5, breaking engagement between 'the terminal contact H0 and sta tionary contact I06, the solenoids 91 will be deenergized. The micro switches I05 are operated individually as soon as the abrading tool associated with each switch is expanded to the preset working expansion limit and operates its micro switch. Operation of a micro switch brings the terminal contact IIO into engagement with stationary contacts I01 in order to energize the solenoids 96 through the power circuits including the power line II2, the spring conductors III, terminal contacts IIO, conductors II5, and completes the circuit of the power line II3 through the coils of the solenoids 96. As soon as all of the micro switches I05 have been thrown to the left hand position, the circuit is closed between the power line II2 through the conductor I23 of the extreme right hand micro switch I05 to the contacts III which at this time engages the stationary contacts II6 of that switch and thence through all of the contacts III and N6 of the other switches to the conductor I20, the winding of the solenoid I2I and conductor I22 to the power line I I3. This effects energization of solenoid HI and reverses the action of control valve I causing the hydraulic cylinder 24 to elevate the spindle head I6. Energization of the soleoids 96 has in the meantime caused fluid pressure delivered from the pump I through the solenoid operated valves 84 and conduits 94 to the pressure chamber 03 to elevate the .piston II in order to cause contraction of the tool heads 22 prior to their withdrawal from the bore II of the work piece I0. As soon as all of the pistons II have been elevated to the uppermost position, the springs ml for control plungers I00 have returned the latter to their right hand position. A slide bar I38 provided with pins I39 engageable with each snap spring conductor III of the mi- III cro switches may be moved to the right to return the snap springs III to the positions depicted in full line in Figs. 4 and 5. This places the abrading machine in condition to perform the desired operation upon the next work piece.

Many changes could be made in the above described constructions, and many apparently widely different embodiments could be had without departing from the spirit and scope of the present invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrated and not in a limiting sense.

What is claimed is:

1. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including expansible and contractable fluid pressure responsive means for expanding and contracting the abrading tool, a source of pressure fluid for said fluid pressure responsive means, valve means for directing pressure fluid from said source selectively into either end of said fluid pressure responsive means selectively to expand or contract the abrading tool, and means operable in response to a predetermined expansive movement of said fluid pressure responsive means for operating said valve means.

2. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including expansible and contractable fluid pressure responsive means for expanding and contracting the abrading tool, a source of pressure fluid for said fiuid pressure responsive means, valve means for directing pressure fluid from said source selectively into either end of said fluid pressure responsive means se lectively to expand or contract the abrading tool, and means operable in response to predetermined expansive movement of said fluid pressure responsive means for reversing the operation of said valve means.

3. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including expansible and contractable fluid pressure responsive means for expanding and contracting the abrading tools, a source of pressure fluid for said fluid pressure responsive means, valve means for directing pressure fluid from said source selectively into either end of said fluid pressure responsive means selectively to expand or contract the abrading tool, and adjustable means operable in response to expansive movement of said fluid pressure responsive means to selective limits for reversing the operation of said valve means.

4. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including a fluid cylinder, a piston in said cylinder, means operable by said piston for expanding and contracting the abrading tool, a source of pressure fluid for said cylinder, valve means for directing the pressure fluid from said source into either end of said cylinder selectively to expand or contract the abrading tool,

and means operable in response to predetermined movement of said piston to operate said valve means.

5. In a grinding or honing machine, in combination, a reciprocating tool support, a plurality of spindles each journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, a tool adjusting means for each tool on said support including expansible and contractablefluid pressure responsive means for expanding and contracting each abrading tool, a source of pressure fluid for all of said fluid pressure responsive means, a valve means for each of said fluid pressure responsive means for directing pressure fluid from said source selectively into either end of each of said fluid pressure responsive means to expand or contract one of the abrading tools, and a-plurality of means each operable in response to expansive movements of one of said fluid pressure responsive means to a selected limit for reversing the operation of the valve means therefor.

' 6. In a grinding or honing machine, in combination, a reciprocating tool support, a plurality of spindles each journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, a tool adjusting means for each tool on said support including expansible and contractable fluid pres-- sure responsive means for expanding and contracting each abrading tool, a source of pressure fluid for all of said fluid pressure responsive means, a valve means for each of said fluid pressure responsive means for directing pressure fluid from said source selectively into either end of each of said fluid pressure responsive means to expand or contract one of the abrading tools, and

1 a plurality of adjustable means each operable in response to expansive movementsof one of said fluid pressure responsive means to selected limits for reversing the operation of the valve means therefor.

7. In a grinding or honing machine for finishing a plurality of cylindrical surfaces in a workpiece, a reciprocating tool support, means for moving said. support toward and away from the work piece, a plurality of, spindles each journaled at one end on said support and adapted to carry on its other end an' expansible and contractable abrading tool, a tool adjusting means for each tool on said support including expansible and contractable fluid pressure responsive means for expanding and contracting each abrading tool, a source of pressure fluid for all of said fluid pressure responsive means, a valve means for each of said fluid pressure responsive means for directing pressure fluid from said source selectively into either end of each of said fluid pressure responsive means to expand or contract one of the abrading tools, a plurality of means each operable in response to expansive movement of one of said fluid pressure responsive means to a selected limit for reversing the operation of the valve means therefor, and means operable in response to such reversal of operation of all of said valve means for causing said ing a plurality of cylindrical surfaces in a workpiece, a reciprocating tool support, means for m0ving said support toward and away from the workpiece, a plurality of spindles each journaled at one end of said support and adapted to carry on itsother end an expansible and contractable abrading tool, a tool adjusting means for each tool on said support including expansible and contractable fluid pressure responsive means for expanding and contracting each abrading tool, a source of pressure fluid for all of said fluid pressure responsive means, a valve means for each of said fluid pressure responsive means for directing pressure fluid from said source selectively into either end of each of said fluid pressure responsive'means to expand or contract one of the abrading tools, a plurality of adjustable means each operable in response to expansive movements of one of said fluid pressure responsive means toselected limits for reversing the operation of the valve means therefor, and means operable in response to such reversal of operation of all of said valve means for causing said first named means to move said support relative to said workpiece. h

9. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including a fluid cylinder, a piston in said cylinder, means operable by said piston for expanding and contracting the abrading tool, a source of pressure fluid for said cylinder, valve means for directing the pressure fluid from said source into either end of said cylinder selectively to expand or contract the abrading tool,

means operable in response to predetermined I movement of said piston to operate said valve means, and positive stop means on said spindle for limiting expansion of said abrading tool in the event of failure of said last named means to act,

10. In a grinding or honing machine, in combination, a reciprocating tool support, a spindle journaled at one end on said support and adapted to carry on its other end an expansible and contractable abrading tool, tool adjusting means on said support including a fluid cylinder, 2. piston in said cylinder, means operable by said piston for expanding and contracting the abrading tool, a source of pressure fluid for said cylinder,

valve means for directing the pressure fluid fromsaid source into either end of said cylinder selectively to expand or contract the abrading tool, means operable in response to predetermined movements of said piston to operate said valve means, positive stop means on said spindle for limiting the expansion of said abrading tool in the event of failure of said last named means to act, and a manually adjustable means for setting said positive stop means.

-' JOHN E. KLINE.

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